Precision electrical component



Nov. 16, 1965 J. M. HOYTE 3,217,390

PRECISION ELECTRICAL COMPONENT Filed March 2, 1962 7 r ll/14420001114 gINVENTOR JOHN M. HOYTE ATTORNEY United States Patent 3,217,390 PRECISIONELECTRICAL COMPONENT John Merrishaw Hoyte, Palo Alto, Califrl, assignort0 Hewlett-Packard Company, Palo Alto, Calif., 21 corporation ofCalifornia Filed Mar. 2, 1962, Ser. No. 177,023 1 Claim. (Cl. Z9155.62)

This invention relates to a precision electrical component such as awound resistor.

The main object of this invention is to relieve the stresses imposed ona wire wound on a core. A change in the stress on the wire of a woundresistor changes the cross-sectional area of the wire and therefore itsresistance.

Referring to the drawing, FIGURE 1 shows a core 3 made of a deformableelastic material such as Dow Corning Silicone Rubber No. 80. This core 3is provided with end flanges 5 and with an axial aperture through whicha bolt 6 provided with a head 7 and a nut 8 may be inserted. BeforeWinding the wire 9, the nut is turned until the core 3 is compressed,thus reducing its length and increasing its diameter. The wire 9 is thenwound in planes perpendicular to the axis of the core. When this isdone, the bolt 6 is removed, thus reducing again "ice the diameter ofthe core and leaving the winding somewhat loosely thereon. Thus there isno need to match the coefficients of expansion of the core 3 and of thewire 9.

I claim:

The method of making a precision electrical component including a wireand a permanent, deformable elastic core, said method comprising thesteps of subjecting said core to a compression force along an axis toincrease uniformly the diameter of said core, winding said wire on theexpanded surface of said core in planes substantially perpendicular tosaid axis, and releasing said compression force to leave said windingsomewhat loosely mounted on said core.

References Cited by the Examiner UNITED STATES PATENTS 3/1877 Curtis etal. 29-155.57 8/1951 Dougherty 242l10

